Pitch



Patented Apr. 24, 1945' UNITED STATES. PATENT OFFICE PITCH Donald A. Lister/Brunswick, Gag, assignor to Hercules Powder Company, Wilmington, Del-.,

a corporation of Delaware l No Drawing. Original application Dece nber 27,

1940, Serial NO. 372 002. Divided and this application October 24, 1944, Serial No. 560,203

3 Claims. (o1. zoo-10.6

This invention relates. to the production of new materials frompine wood resin containing at least of gasoline-insoluble resins.

The prior art is concerned with the manufacture of rosin oil from rosin anduse thereof inthe manufacture of various materials such as lubricants and varnishes. The manufacture of rosin oil is disadvantageous because the yields-of rosin pitch and rosin oil are not always desirably high, and the rosin oil and pitch soproduced have not had properties adapting them formany usesr In addition, the properties and characteristics of the products have been subject towide variation in quality and to premature deteriorationupon .It is an object of the present invention to provide an improved pine wood resin pitch.

In accordance with the present inventiomthis object is accomplished by destructive distillation of a resin derived from pine wood and which contains at least about 35% of'gasoline-insoluble resinous material. The resinous material. employed in carrying out the present invention'is characterized by being substantially completely resinous throughout, and by a content of at least about 35% by weight of gasoline-insoluble resinous material The material is further charac terized by being almost completely soluble in such liquid aromatic solvents. as benzene, toluene,. xylene, etc. l

as isobtained by extracting. pine wood with benzene, consists of palerosin, gasoline-insoluble resinous material, and oolorbodies. Uponthe treatment of such resinous extract to separate therefrom a fraction of pale rosin, there isformed one i or more fractions containing the balance: of the resinous material derivedfrom the pine. wood.

My invention may use one or more or such re-- maining fractions as the raw material. Such'raw material may be derived by the purification of wood rosin and is characterized by a relatively high content: of gasoline-insoluble resinous ma--.

terial; that is, at least 35%. The'non-rosin: por-' tion, ofi'thepine wood extract may be separated by appropriate processes into a traction of substantially gasoline-insoluble resinous materialand a dark-colored intermediate fraction lying-between the substantially gasoline-insoluble fraction and rosin. It is impossible-to efiect an ab-u solutely clean separation between the gasolineinsoluble resinousmaterialand the rosin. By the preparation of a dark-colored intermediate fraction containing some gasoline-insoluble resinous material and the color bodies, a, very goodseparation of the pine woodextract into rosin, gasoline-insoluble resinous material, and into thisintermediate fractiomis efieoted.

I may use as the resinous raw material the dark-colored intermediate fraction largely in soluble in petroleum hydrocarbons and obtained by the refining of impure wood rosin to pale grades by means of a selective solvent for color bodies such as furfural, or a selective absorbent such as fullers earth. Such anitnermediate fraction contains at least 35% and usually at least 50% by weight of gasoline-insoluble resinous material. Stilliurther, I may use the substantially completely gasoline-insoluble resinous material derived from pine wood, and which contains at least about 85% by weight of. gasoline-insoluble resmousmat'erial. Mixtures-of theforegoingresv Thetotal resinous extract of pine wood, such it is preferable to employ as the raw material pine wood resin containing from about 50% to about of gasoline-insoluble resinous terial.

The dark-colored fraction referred to above is a product resulting from the process used in decolorizing rosin. For example,,so-calied FiF'rosin,

which is ruby red. in color and is derived from pinewood by extraction with benzene followed by evaporation: ofthe benzene and extraction of the resinous residue with a petroleum hydrocarbon such. as hot petroleum ether or hot gasoline, is deeolorized by adding. furfural tothehot solution, agitating. the mixture, and then allowing the'mixture to-form a; liquid-layer system in which 3 and therefore is only partially soluble in petroleum hydrocarbon solvents at room temperature.

The percentage of gasoline-insolubles varies from about to about by weight. It has a higher flow point, a much higher viscosity, lower acid number, and a higher unsaponifiable content than FF wood rosin. However, the saponification number is not correspondingly lower, indicating a high ester content. In addition, it is non-crystallizing. Such a fraction ischaracterized by the following approximate analysis:

C. and preferably above about 90 C., and an acid number of not over about 140.

In accordance with the present invention, the resinous raw material is destructively distilled, preferably in an inert atmosphere such as carbon dioxide, and in either the presence or absence of a decarboxylating catalyst. An example of a preferred decarboxylating catalyst is p-toluene sulionic acid. Examples of other decarboxylating catalysts are: fullers earth, zinc chloride, phosphoric acid, benzene sulfonic acid, phosphorus pentoxide, and sodium acid sulfate.

The resin is destructively distilled at a temperature suflicient to effect formation of a resinous oil by decomposition of the resin and sufi'icient to form a residual pitch in the still. Distillation temcovering from about 330 C. to about 375 C., and

still more preferably from about 355 C. to about 370 C. In general, temperatures below about 355 ,C. do-not cause the desired decomposition of the Unsaponifiables per cent 10-20 Gasoline insolubles do 35-75 Acid number 100-130 saponification number 140-150 Melting point (drop) C -95 Atypical example of such a fraction had the followinganalysiszacid number, 124; saponification number, 150'; melting point (drop), 89 C.; gasoline insoluble, 57%; unsaponifiable matter, 12%; Lovibond color, dark; ash content, 0.03%.

The substantially gasoline-insoluble fraction referredto above may be prepared from pine wood by the processes set forth in U. S. patents to Hall, Nos. 2,193,026 and 2,221,540. This fraction is characterized by being substantially completely insoluble in petroleum hydrocarbons such as gaso- I line. The gasoline-soluble portion of this fraction rarely exceeds 15% by weight. This fraction may be said to be the gasoline-insoluble resin .con

taine'dinlpine wood. For example, the extraction,

of pine'woodwith benzene yieldsa' mixture of this fraction and FF rosin.. Upon commingling the molten resinous mixture with a mixture of gasoline and a relatively smallvolume of furfural, the.

fraction in question goes into solution inthe furfural, while theFF rosin goes into solution in the fractionis in general characterizedby a methoxy contentoi from about 3% to about 7.5%, an acid number of from about 90 to about 110, a melting point (drop method) of from about C. to about C., petroleum ether or gasoline-insolubility of about85% or more, andasaponification number of from about to about 145. A typical specimen had the following characteristics: Drop meltingpoint, 115 C. acid number, 93; gasolinesoluble matter, 12%; toluene insoluble matter, 20%; saponification number, ash content,

In general, the resinous raw material which is employed in carrying out the present invention and which is typified by the dark-colored inter mediate fraction of color bodies referred to at length above, or the substantially completely gasoline-insoluble fraction, or blends thereof, may be defined as a resin naturally occurring in pine wood and characterized by a gasoline-insolubility of 35% or more, unsaponifiable content of from about 5% to about 20%, melting point above 85 resinous 'raw material, while temperatures above about 370 C. tend to produce free carbon in the residue which is undesirable. Heating periods of from about 30 minutes to about 25 hours are operable depending upon the temperature and pressure maintained, size of charge, presence or ab sence of decarboxylating catalyst, etc. In general,

the distillation is continued until the resin has pressure, atmospheric pressure, or at super atmospheric pressure. I Y I The distillate comprises non-condensable gases, spirits or low b6iling material boiling below about 100 C., a substantial amount of'water, and an oily material boiling above 100 C. Preferably the oily portion of the distillate boiling above theboiling point of water is separated from'the aqueous portion in any suitable manner and constitutes the resin oil. If desired, this oily portion of the dis-' tillate may be'completely freed from any traces of water in any suitable manner as for example, by heat or by suitable chemical treatment. The oily portionmay be re-distilled, if desired, for further purification and the product passing over below a vapor temperature of about 250 C, (at atmospheric pressure) collected. Alternatively,

" that portion of the distillate from the destructive The destructive distillation may suitablybe car- I ried out under reduced pressure (for-example 110- I 600 mm. of mercury, with rapid removal andcondensation of'distillate) The distillation may 'be conducted at atmospheric pressure provided the temperature in the still is carefully controlled.

Destructive distillation may be followed bysteam' distillation using superheatedsteam. Or superheated steam may be'employed throughout'the distillation, whether at sub-atmospheric, atmospheric, or superatmospheric pressure] Distillais advantageous because it maintains "the tempera-- 'ture of thecharge at the desired level and in as carbon dioxide, steam,'nil;ro-

manner action mixture in any: suitable manner to remove the non-condensable gases, the; waterlfthe spirits, andithe oils.

The distillation maybe stoppedpriorto tam.

plete decomposition of the resinous raw material, for example, at a point where the amount of residualpitch formed varies from say about 30% to about 75%.,by=;weight of the original resinous material depending upon the properties desired in the pitch. w

The yield of pitch ranges upwardly from about 30% by weight'based on the weight of original resin. The yield of resin oil may range from, about 20% toabout 60% byweight. ofthe orig-' inal resin. The percentage of waterjwillusually" run fromabout 5% to about by weight. The percentage unaccounted "for non -condensable gases, spirits, and mechanical losses) will usually range from about 5% to about byjweight oftheoriginalresin. s V s The relative proportions of resin 'oilj and pitch obtained by thedistillat'ion willldep'end' upon the. particular raw material employed, the tempera-.

ture of treatment, and otherv factors. Generally speaking, however, the percentage of oil obtained will vary between about 10% and about 10G 75 by weight of the pitch.

modification be effected, by qontinuousoperation, for example, with a. still into which molten resinous raw material is continuously'passed and subjected to a temperature from about 300 C."

to about400 C. while continuously removing and cooling the distillate. Continuous operationin,

for carrying out the process." A J The products of the present invention are capable'of wide application inthe arts. 'I'hefresin oil products may be used in the manufacture of cable insulation, transformer oils; printing inks, greasesand lubricantsjvarnishes and similar coating compositions, in oil'cloth and linoleum, in

any other suitable manner may equally-be used brewers" pitch, in place of creo'sote in thepreser -f vation of wood andin flotation processes, the

manufacture of and reclaiming of rubberjfetc: The oils are charcterized by a substantial; content of phenolicconstituents'or derivatives this content increasing with the content of gasolinehile the distillation will" generally eate ducted bya batch operation, it may with suitable bodies, a saponificationinumber below 100: and usually below 60, an acid number below 50 and usually below 30, a methoxy content of from about 1% up to about 6%, substantially complete solubility in benzene and: the. like, boiling point rangeof: from about 200 C. to about 360" C., relatively hig'h 'gasoline-insolubility; specific. gravity above 1.0 and refractive index of from. about" 1.540 to-about"1.5'70-. Riosin oil typically has a refractive indexof about 1.530. M i r i The pitchy products of the present invention are characterized by complete freedom from I acetic acid or other volatile or unstable organic aside, a .very substantial, content of. phenolic bodies, a saponification number below 100 and, usually below 60,; an acidnumber .of from about. 30*,t0kflbQLlt; 50, an. unsaponifiableconte-nt of at; least5(l%,, amethoxy content'of from about 1% V to about 6%, substantially: complete solubility in,

benzene and the like, and a substantialcontent of gasoline-insoluble material, this content dependingupon the gasoline-insoluble content of ,'.the resinous raw materialgfl s s new e gi e s v re e examples in accordance withthe present invention- Example 1 A charge of dark-colored pine. wood resinous fraction (gasoline-insoluble 57%): weighing 600 g. was distilled at 330-360" C. for 7 hours in an atmosphere ,of carbon dioxide; thegvolatile oils and. water which distilled. off were continuously condensed and separated. Yields of 9% of resin; residualpitch wer oil, 5% of. water, and 80% of obtained. M,

E am e A mixture of 450 g. of dark-colored pine wood resinous fraction (gasoline-insoluble 57%), 150

s g. 3 of substantially completely gasoline-insoluble insoluble in the" original resinous raw material.

The pitchproduo'ed may be employedin the protectionofrope, cordage and the like, in the man-' u'factureof oakum, in rubber compounding, in the manufacture 'of so-called tar tape," in the manufacture of formaldehyde resins to which it IS particularly suited because'ofitszhigh content of phenolic constituents, in brewers pitchfletc. The products of the present invention'areiextremay resistant to influences which normally tend to decompose and deteriorate the usuafrosjin oil or rosin pitch; such asweathering; heat lightp moisture, water, chemicalinfiuences, etc; i i

The, oily products of the; present invention are' and: condensed. The condensate comprised 20 360 C. for4 /2 hours.

pine "wood resin (gasoline-insoluble 88%) and" 0 .6 g. of p-to'luene sulfonieacid was charged into a Stillai'1d"distilld at 340-360 .C. for one hour in an atmosphere of carbon dioxide.

Yields of 21% oils, 4% water and residual pitch wereobtained.

Example 3 l A- charge of dark-colored pine wood resin (g asoline-insoluble 51%) weighing 175'0jg. was distilled inan atmosphere of carbon dioxide at The yields were 1300 g, pitch, g. oils, and 82 g. of water.

s fExample 4 I Acharge of1560-gallonsof molten dark-colored." plne WOOd resinous: fraction (gasoline-insoluble 53-55%). was placed in a :direct fired still and heated to 360 1638: hours were: required to-ireach; this temperature, The chargewas distilled at this temperature for 3.hrs.. i The entire=distillate comprisingiwaterand oils was continuously removed gallons of water and 748 gallonsof oils. The re-' sidual pitch had a volume of 752 gallons or48.1

pine 'wood resinous fraction (gasoline-insoluble" characterized in general by complete freedom 7'5 62%) was placed in a still, brought to 360C, and,

. from aceticzacid: or: other volatile orundesira-ble' I organic acids,a substantial contentonphenolic Thebils and water which distilled offwere separated.

distilled at this temperature for one hour. The

condensate contained 687 gallons of.-oilsand the-v residual pitch amounted to 813 gallons. Example 6 p A mixture of 600 g. :of substantially'gasolineinsoluble pine, wood resin (gasoline-insoluble 92%) and 0.6 g. of p-toluene sulfonicacid was distilled at 340-360". C. in an atmosphere, of CO2 for hour. .The oils (129 cc.) and the Water (30 cc.) which distilledofi were condensed and separated from oneanother. The residual pitch amounted to 345 g. s

v 4 Example 7 A mixutre of 600 g. of dark colored pine wood resinousfraction (gasoline-insoluble 57%) and 0.6g. of p-toluene sulfonic acid was heate'd at 340-660 C. for one hour in an atmosphere of CO2. Yields of 21% oils, 4% Water, and 65% residual pitch were obtained.

Example 8 1 A mixture of 300 g. ofdark-coloredpine wood resinous fraction (gasoline-insoluble 58%) and 300 g. of substantially gasoline-insoluble pine wood resin (gasoline-insoluble 92%) was distilled at 340-360 C. for four hours in an atmosphere of CO2. Yields of 15% oils, water and 70% of pitch were obtained.

Example 9 I A200 g. lot of substantially gasoline-insoluble pine wood resin (gasoline-insoluble 90%) wasdestructively distilled by heating on a sand bath under atmospheric pressure up to about 380 C. The condensed distillate comprised 80 g. of oils. The residual pitch amounted to 90 g.

Example 10 A lotof- 200 g. of substantially gasoline-ins0luble pine Wood resin (gasoline-insoluble 89%) was distilled at atmospheric pressure, ,coolingall of the distillate up to distillate vapor temperature of 220 C. The conduct of the distillation was as follows: I

The oils in the condensate amounted to 41.5 g. or 20.75% on the weight of the resinous raw material, the water to 10.5 g., and the pitchy residue to 127.5g. Unaccounted for was 20.5 g.

The pitches produced in accordance with. the present invention are characterized by a relatively high gasoline-insolubility, which is in generalproportional to the gasoline-insolubility of the original resin. Thus, the pitch ,obtainedxfrom a series of distillations of the intermediate resin.

of 35-75% gasoline-insoluble contained on an average about 32% gasoline-insoluble, whilerthat from the substantially gasoline-insoluble .resin' (85% or over gasoline-insoluble) contained over 75% of gasoline-insoluble.

Comparative analyses of typical resin oils produced by the present invention withrosin oil are as follows: r

T 081 .1 a re oil Y Typlclal rgsir; oil 32223 2 pro uce rom 33%? intermediate 2 3:3

. I resin (35-75% G. insoluble L) resin (85% or more (1.1.)

Acid number. 17.19 35.0. Saponification 100.0.

umber. Benzeneinsoluble .Nil Nil. Flash ninr 99 C Viscosity (Say- 160 sec. at

bolt). 100 F. Sp. gr.20.0/ 15.6-.. 0.9742 1.05. .Iodme number.... .65.

Boiling range... 5%95% Temperature dropped.

These analyses are only representative of the oils as the analysis of an individual oil is dependent upon the particular resin distilled and 'the particular' method of distillation. However, they generally indicate the marked differences between the resin oils produced by the present invention androsin oil.

In the copending application of P. A. Ray, Serial No. 360,263, filed October 8, 1940, now US. Patent 2,273,725, there is described the manufacture of 'a tar by blending the oily distillate with the pitchy residue. In the copending application of P. A. Ray, Serial No. 363,700, filed October 31, 1940, now U. S. Patent 2,341,289, the use of such a tar as a rubber softener is described and claimed,

It will be understood that .the details. and excation, Serial No. 372,002, filed December27,

What I claim and desire to protect by Letters Patent is:

1, As a new article of manufacture, a pitch constituting the pitchy residue derived by destructivedistillation of a pine wood resin containing at least about 35% of gasoline-insoluble resinousrnaterial at a temperature suflicient to r effect formation of a distillable'resin oil and a residual pitch by decomposition of the resin for a sufiicient length of time to decompose said resin to .resinoil and resin pitch but ins'ufllcientto convertsaid pitch to coke, the pitch being further characterized by having substantial freedom from volatile and unstable organic acids, an acid number'of from about 30 to about 50, an unsaponifiable content of at least about 50%, a contentof phenolic bodies, a methoxy content of from about 1% to about 6%, and substantially complete solubility in benzene.

2. As a new article of manufacture, a pitch constituting the pitchy residuederived by destructivedistillation of a pine wood resin containing at least about of gasoline-insoluble resinous material at a temperature sufli-cient to efiect formation of adistillable resin oil and a residual pitch by decomposition of the resin for a sufficient length of time to decompose said resin to resinoil and resin pitch but insuificient to convert said pitch to coke, the pitch being further characterized by having substantial freedom cient to efiectformation of a distillable resin oil and a residual pitch by decomposition of the resin for a sufficient length of time to decompose said resin to resin oil and to resin pitch but insufficient to convert said pitch to coke, the said pitch being further characterized by having sub stantially complete freedom from volatile and unstable organic acids, an acid number of from about 30 to about 50, an unsaponifiable content of at least about 50%, a methoxy content of from about 1% to about 6%, and substatially complete solubility in benzene. y

' DONALD A. LISTER. 

